Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOC192 > Lecture 39: OBESITY > Flashcards

Lecture 39: OBESITY Flashcards

1
Q

How does the WHO classify obesity?

A

By BMI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the formula for BMI?

A

weight(kg)/height(m) ^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a BMI >30?

A

Obese

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a BMI 25 to 30?

A

Overweight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a BMI 20 to 25?

A

healthy weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a BMI <20?

A

Underweight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What increases with increasing BMI?

A

Risk of type 2 diabetes and CHD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What may abnormal TAG storage in muscle and liver contribute to?

A

Insulin resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do 90% of people return to original weight?

A

By diet and exercise meaning that they lose fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is metabolic rate made up of?

A

Adaptive thermogenesis (smallest component), physical activity and obligatory energy expenditure (largest component)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is adaptive thermogenesis?

A

Variable, regulated by the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does adaptive thermogenesis respond to?

A

Temperature and diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where does adaptive thermogenesis occur?

A

In brown adipocyte mitochondria, skeletal muscle and other sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is physical activity?

A

Variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is obligatory energy expenditure required for?

A

Performance of cellular and organ function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when respiration is uncoupled to oxidative phosphorylation?

A

Heat is produced rather than ATP as the ETC goes faster to try and re-establish the gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where were uncoupling proteins originally found?

A

In brown fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where are uncoupling proteins present?

A

In the inner mitochondrial membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are uncoupling proteins?

A

Regulated proton channels in the membrane (“holes”) which remove the proton gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is an example of an uncoupling protein?

A

2,4 - dinitrophenol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do uncoupling proteins do?

A

Uncouple ATP synthesis from fatty acid oxidation which causes the electrochemical potential gradient to dissipate releasing heat which therefore increases metabolic rate and burns excess fuels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When are proton channels open and closed?

A

Open in cold and closed in warm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How are UCP’s regulated?

A

By the sympathetic nervous system (SNS)/noradrenaline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the main neurotransmitter of the SNS?

A

noradrenaline

25
Q

What is brown fat?

A

Special thermogenic tissue

26
Q

Where is brown fat found?

A

In hibernating animals, babies and less in adults

27
Q

What does brown fat do?

A

Keeps hibernating animals and babies warm

28
Q

What does brown fat have?

A

Many mitochondria and fat droplets

29
Q

What is the metabolic adaptation to cold in penguins?

A

avian uncoupling protein (avUCP)

30
Q

Where is avUCP highly expressed?

A

In the mitochondria of pectoral muscles

31
Q

What does avUCP do?

A

Oxidises fatty acids to generate heat

32
Q

What has recently been discovered?

A

Uncoupling proteins (UCP2, UCP3) in white adipose tissue and in muscle of humans as well as other animals

33
Q

What may UCP2 and UCP3 do?

A

Act to raise the metabolic rate and release heat to burn off some excess energy and prevent obesity

34
Q

What are some strategies to combat obesity (involving BAT)?

A

stimulate existing BAT, switch on brown fat differentiation and growth, transplantation of engineered BAT

35
Q

What may be involved in switching on brown fat differentiation and growth?

A

PRDM16 promoter inserted into developing white adipose tissue to promote brown adipose tissue growth

36
Q

What does the in vivo approach: pharmaceuticals, biologics and natural components to BAT involve?

A

increase BAT differentiation from progenitor cells, activated BAT - mediated thermogenesis, promote muscle thermogenic function and increase general mitochondrial uncoupling

37
Q

What is involved in the ex vivo: cell based therapy approach?

A

1: isolate progenitor
2: induce in vitro with agents promoting BAT differentiation or genes specifying BAT differentiation
3: transplant back to donor to generate functional BAT

38
Q

What is the component of obesity from genes?

A

30-80%

39
Q

What is also involved in obesity other than genetics?

A

Environmental and lifestyle factors

40
Q

What are the genetic defects in rodents?

A

Obese mouse ob/ob
diabetic obese mouse db/db
fatty rat fa/fa

41
Q

What does the obese gene code for?

A

leptin - a 16kDa protein

42
Q

What does the mutant obese mouse (ob/ob) do?

A

Not produce leptin

43
Q

What is leptin?

A

A peptide hormone secreted from fat cells

44
Q

What does leptin do?

A

Signals the brain to decrease food intake, increase energy expenditure and therefore maintains normal animal in energy balance

45
Q

Where is the leptin receptor found?

A

In the hypothalamus of the brain and several other tissues

46
Q

Where is the leptin receptor absent?

A

In the obese diabetic (db/db) and the fatty rat (fa/fa)

47
Q

What are some obese humans found to have?

A

mutant leptin or leptin receptor

48
Q

What do most obese humans appear to be?

A

Resistant to the leptin signal

49
Q

What did the severely obese child have?

A

No serum leptin, homozygous for frameshift mutation in the leptin gene

50
Q

What treatment was the severely obese child given?

A

Recombinant leptin therapy for a year

51
Q

What did the treatment do for the severely obese child?

A

Decreased food intake and 16kg weight loss in 1 year due to fat oss

52
Q

What are some other defects in the cell signalling pathway of leptin which cause obesity?

A 
MC4R = 4-6% of severe human obesity
POMC= bariatric surgery may be required
53
Q

What are factors influencing the development of obesity?

A

genes, monogenic syndromes, susceptibility genes, exercise, food intake, culture and environmental factors

54
Q

What are potential molecular targets for anti-obesity drugs?

A

Food breakdown, satiety signals, mitochondria and brown fat as well as microbiome

55
Q

What can be targeted for food breakdown?

A

Pancreatic lipase may be blocked so less fat is absorbed (xenical)

56
Q

What can be adjusted in satiety signals?

A

Increase leptin levels (leptin receptor), gut satiety factors -clinical trials underwya

57
Q

What can be targeted in mitochondria and brown fat?

A

Uncouple oxidative phosphorylation from electron transport and up regulate uncoupling proteins with drugs increasing functional BAT (future?)

58
Q

what does leptin stimulate?

A

Sympathetic neurone activation > lipolysis

59
Q

What is adipose tissue?

A

An endocrine organ which secretes regulatory molecules which is why having too much can disrupt the pathway

BIOC192 (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions